European Union flags fly outside the European Commission building in Brussels, Belgium, on June 9, 2021.(Photo: Xinhua)

The European Union (EU) "will start collapsing" unless it challenges a ruling by Poland's top court that national legislation trumps European laws, a senior official with the bloc said on Monday.

Poland's constitutional tribunal ruled against the central tenet of European integration last week, sharply escalating a row over fundamental values between eurosceptics ruling in Warsaw and most of the other 27 EU countries.

More than 100,000 people protested in Poland on Sunday in support of the EU, sounding the alarm about what they fear is a prospect of their country following Britain and leaving the bloc in a "Polexit."

"If we don't uphold the principle in the EU that equal rules are respected the same everywhere in Europe, the whole Europe will start collapsing," said Vera Jourova, EU Commissioner from Poland's neighbor, the Czech Republic.

"That is why we will have to react to this new chapter which the Polish constitutional court started to draw," said Jourova, in charge of values and transparency at the executive European Commission.

One way or another, the tribunal ruling is likely to cost Warsaw.

It follows prolonged and divisive disputes in which Poland stands accused by many Western countries, international rights watchdogs and advocates of curtailing the independence of media and courts, as well as infringing on the rights of women, migrants and LGBT people since the Law and Justice (PiS) party won power in 2015.

The commission, the guardian of EU treaties, is already withholding its approval for Poland's recovery plan necessary to let Warsaw tap into billions of euros available on top of other handouts from the bloc and meant to help revive economic growth mauled by the novel coronavirus pandemic.

Apart from blocking the disbursement of COVID recovery funds to Poland, the commission might press ahead with a new and yet-to-be-tested enforcement tool to suspend funding for states deemed violating key values enshrined in European laws.

Other countries in the bloc could revive a stalled probe into the undercutting of democratic rights in Poland, which could go all the way to suspending Warsaw's vote in the bloc. But that is unlikely.

The Brussels-based commission could also launch a new legal case against Warsaw for violating EU laws. It could culminate in the European Court of Justice (ECJ) slapping penalties on the Polish government.

Reuters